Bela Lugosi

Dr. Feodor Orloff / Prof. John Dearborn

Hugh Williams

Det. Insp. Larry Holt

Greta Gynt

Diana Stuart

Edmon Ryan

Lieutenant Patrick O'Reilly

Wilfred Walter

Blind Jake

Arthur E. Owen

Dumb Lou

Alexander Field

Fred Grogan

Gerald Pring

Henry Stuart

O.B. Clarence

Prof. John Dearborn (voice)

May Hallatt

Police Constable Griggs

Bryan Herbert

Police Sgt. Walsh

Charles Penrose

Morrison, undercover detective

Julie Suedo

Orloff's Secretary

Walter Summers